Sight triangle: A triangular shaped portion of land established for unobstructed visibility of motorists entering or leaving a street or driveway intersection in which nothing, whether stationary or movable (i.e., vehicles, vehicular maneuvering area, signs, landscaping or objects of any kind) is permitted to be located between a height of two and one-half (2½) and eight (8) feet above the elevation of the adjoining edge of pavement. An exception to the prohibition is a tree with clear trunk between two and one-half (2½) and eight (8) feet. Sight triangles shall be provided at the following locations:
1. The intersection of an alley or street and a driveway, or
2. The intersection of an alley and a street, or
3. The intersection of a street and a street.